March 10, 2016

"In 1973, a small group of astronomers from around the globe had a secret weapon for seeing a longer eclipse than ever before: a prototype Concorde, capable of chasing the eclipse across the Earth at twice the speed of sound."

'Climbing up into the stratosphere at an altitude of 56,000 ft., [André] Turcat pushed the aircraft to Mach 2.05, more than twice the speed of sound. Even after a couple of test flights the atmosphere on board was tense—the timing and the equipment had to work perfectly. Helped by Concorde’s two onboard inertial guidance systems, the crew guided the aircraft along the carefully-mapped trajectory and met the eclipse within 1 second accuracy of the planned rendezvous. The chase was on.

'“Alone in the Mauritanian sky,” as a French film about the flight poetically put it, Concorde 001 hurtled east along the path of totality. With the eclipsed sun high over ahead, Turcat switched on the night-time navigation lights in the midday darkness. Paintings and stamps issued by various African countries would depict the epic, sci-fi sight, and Turcat would later deliberate about whether to file the flight as a day or night one.

'In one flight, Concorde had given astronomers more eclipse observing time than all the previous expeditions last century—generating three articles in Nature and a wealth of new data. But today [Pierre] Léna, who has recently published a book in French and English about the experiment, Racing the Moon’s Shadow with Concorde 001, is modest about what it accomplished.

'“The five experiments all succeeded, but none of them revolutionized our understanding of the corona,” he says in a disarmingly honest way about the flight’s immediate impact. “They all played their role in the normal progression of scientific knowledge, but there were no extraordinary results, it has to be said.”'